From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir@xensource.com>
Subject: Re: trap/interrupt gate for hypercall
Date: Tue, 15 May 2007 16:02:07 +0100
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To: "Tian, Kevin" <kevin.tian@intel.com>, xen-devel@lists.xensource.com
Cc: "Liu, Jinsong" <jinsong.liu@intel.com>
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On 15/5/07 15:43, "Tian, Kevin" <kevin.tian@intel.com> wrote:

> Just a curious question about IDT descriptor type for hypercall. What's
> the reason to use interrupt-gate type (14) for hypercall (0x82) on 32bit
> 
> Xen?

Everything's an interrupt gate on 32-bit Xen, so that we can safely
(atomically) save away guest segment register state. NMI is the only real
pain, and I suppose MCE too. Coincidentally Jan just emailed about this very
point.

 -- Keir